The primary objective of this study is to examine the microvascular complications in the streptozotocin diabetic rat model. It will compare age-matched normal rats, diabetic control rats without any treatment, diabetic rats with insulin injections, diabetic rats receiving continuous insulin via mini-pumps, diabetic rats receiving insulin from implantable discs, streptozotocin non-diabetic controls with islet transplanted rats totally and partially reversed transplanted both acutely and after a 6-month delay. We will document clinical data such as daily urine volume and glucose, body weight, and blood glucose as well as glucose tolerance testing. Ocular fluorophotometry and hemoglobin A1C determinations will also be made on a regular basis. At the end of the one year study, biopsies will document the development of the complications in these 10 groups of rats. This study should determine how effective each of these treatments is in the prevention of the diabetic complications at least in this experimental model.